The romantic comedy has Messing playing Kat, a New York-based airline employee on her way to London for her half-sister's wedding, said hollywoodreporter.com.
In order to convince her family and her ex-fiance - who is the best man at the wedding - that she is deliriously happy, Kat hires Himbo Nick (Mulroney), a male escort, as her dream date.
Director Clare Kilner's film is based on "Asking For Trouble", a novel by Elizabeth Young.